Air filter



FIG. 1 is an upper perspective view of the air filter of the present invention;

FIG. 2 is a top plan view thereof;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is a front elevation view thereof the other elevation views being substantially similar; and,

FIG. 5 is a top, front, right side exploded perspective view thereof.

The broken line showing of parts of the drawings is included for the purpose of illustrating use and environment and forms no part of the claimed design. 

CLAIM The ornamental design for a air filter, as shown and described. 